It has been proposed that an international workshop on "The Origin of Pandemic Influenza Viruses" be held in Peking, China, in November, 1982, and this application is for travel and subsistence support for 17 international virologists to attend the meeting. The three most recent type A influenza pandemics of humans were caused by subtypes of the virus which suddenly appeared (or re-appeared) in the human population in China. Historical evidence suggests that previous pandemics also began in this region of the world, but the origin of these "new" viruses is not known. Previous meetings on influenza viruses have focused on the recent developments in sequence analysis, structure and variation in this virus. The present meeting is different in that this expertise will be related to the problem of the origin of pandemic influenza viruses with an immediate view towards seeking explanations that may be available in China and a longer term aim towards stimulating the use of modern molecular biological technology by Chinese scientists. This exchange of information may yield answers in the future on the origin of "new" viruses and what can be done to control them. It is anticipated that approximately 30 overseas scientists and an equal number of Chinese virologists will attend the meeting.